Wide-Angle Optical Imaging Lens for Close-Range Sensing
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Solution Overview
Problem
Current optical imaging lenses face challenges in achieving a large field of view while maintaining low optical distortion and adapting to limited working distances without additional components, particularly in close-range applications such as contactless sensing and access control systems.
Innovation Solution
The optical imaging lens design incorporates a sequence of lens elements including a wide-angle lens, aspherical, molded glass, and free-form surface lenses, optimized to provide a field of view greater than 100 degrees, with a working distance range of 20 mm to 200 mm, and includes an anti-total reflection coating, ensuring improved aberration correction and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a general optical lens design is used, then the working distance can be infinite or far range (200mm to 1000mm), but it cannot achieve close-range application (within 60cm or 30cm) without using multiple lenses or additional components
Solution Approach 1:
The patent applies parameter changes by optimizing the focal lengths, refractive indices, and curvature radii of the six lens elements to achieve a specific working distance range (20mm-200mm) that differs from conventional lenses. The conditional expressions (1)-(6) define specific parameter ranges for lens powers and spacing that enable close-range imaging capability without requiring additional components.
2Area of moving object
If the field of view is increased beyond conventional 60-70 degrees, then wider angle imaging is achieved, but optical distortion increases to 10%-20%
Solution Approach 1:
The patent employs aspherical surfaces on multiple lens elements (first, second, third, fourth, and fifth lens elements) to control optical distortion. The aspherical coefficients enable the lens to achieve a wide field of view (≥100 degrees) while maintaining distortion within acceptable ranges, overcoming the limitation of conventional spherical lenses.
Solution Approach 2:
The six lens elements are designed with multiple functions: the first element provides wide-angle capability, the second and third elements correct aberrations, the fourth element (molded glass) provides structural support and optical correction, and the fifth and sixth elements further refine image quality. This multi-functional design enables simultaneous achievement of wide field of view and low distortion.
3Manufacturing precision
If conventional lens elements are used, then manufacturing is simpler, but aberration correction and image quality are insufficient for wide-angle close-range applications
Solution Approach 1:
The patent uses a combination of different lens materials with specific refractive indices and Abbe numbers. The fourth lens element is specifically designed as a molded glass element, while other elements may use different optical materials. This composite material approach enables superior aberration correction and image quality while managing manufacturing complexity through standardized optical glass types.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables a wide-angle lens with a large field of view and excellent image quality, effectively addressing the need for close-range applications with reduced optical distortion and minimal additional components, enhancing the performance in contactless sensing and access control systems.
Implementation Method 1
The second lens element to the sixth lens element are a combination of aspherical lens element, molded glass lens element, and free-form surface lens element
Implementation Method 2
The second lens element to the sixth lens element are a combination of aspherical lens element, molded glass lens element, and free-form surface lens element
Implementation Method 3
includes an anti-total reflection coating, ensuring improved aberration correction and image quality
Data Source
AI summary
An optical imaging lens adapted to limited working distance is disclosed. The optical imaging lens includes a first, a second, a third, a fourth, a fifth, a sixth lens elements and an image sensing element sequentially along an optical axis from an object-side to an image-side. The first to the sixth lens element each includes an object-side surface facing toward an object-side as well as an image-side surface facing toward an image-side. The first lens element is a wide-angle lens element. The second to the sixth lens element are a combination of aspherical lens element, molded glass lens element, and free-form surface lens element. A field of view of the optical imaging lens is greater than or equal to 100 degrees, and the optical imaging lens is a wide-angle lens.